OFAH Insider: Red swamp crayfish targeted

The red swamp crayfish (Procambarus clarkii) is the latest crayfish discovery in Ontario’s waters.

In the fall of 2024, OFAH Foundation’s Invading Species Awareness Program (ISAP) was contacted about a suspected red swamp crayfish capture from a ditch near Tilbury. Upon confirming the species via a photograph, ISAP staff travelled to Tilbury in late October 2024, and again during a larger collaborative surveillance effort in June 2025.

ISAP staff and partner organizations conducted visual inspections, dug out crayfish burrows, deployed baited traps, and used kick and sweep techniques to try and capture crayfishes. Partners included the Department of Fisheries and Oceans, Ministry of Natural Resources’ Aylmer and Peterborough districts, AECOM, Essex Region Conservation Authority, Lower Thames Valley Conservation Authority, and Trent University.

Dozens of red swamp crayfish captured

Unfortunately, between both follow-up surveillance efforts, dozens of red swamp crayfish were captured using these techniques. This confirms the presence and reproduction of the species in Ontario.

Red swamp crayfish are native to parts of the southern US and are invasive to many parts of North America as well as other continents, like Europe, where they have become a prolific invader. In Canada, they have been reported in British Columbia and on the east coast in Nova Scotia and Newfoundland.

“These reports in Ontario were the first for the province,” ISAP Advisor Brook Schryer said. “The red swamp crayfish is prohibited in Ontario under the Invasive Species Act 2015 and is known to have negative impacts through direct competition with native species through predation and habitat destruction.”

To learn more, visit www.invadingspecies.com. If you’ve seen a red swamp crayfish, take a photo, note your location, and report it to the Invading Species Hotline at 1-800-563-7711 or report online at www.EDDMapS.org.

Originally published in the Ontario Out of Doors 2025-2026 Hunting Annual

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